Unique ID: (from PFRA database) Location: Nenagh, Co. Tipperary. Stage 1: Desktop Review

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1 Location: Nenagh, Co. Tipperary Unique ID: (from PFRA database) Initial OPW Designation APSR AFRR IRR Co-ordinates Easting: Northing: River / Catchment / Sub-catchment Nenagh River / Nenagh / Shannon Type of Flooding / Flood Risk (identify all that apply) Fluvial non-tidal Fluvial tidal Coastal Stage 1: Desktop Review 1.1 Flood History (include review of Floodmaps.ie) River Flow Path The Nenagh River flows past the town of Nenagh on the eastern boundary and meanders towards Lough Derg. Minor tributaries to the Nenagh River are located within the town boundary. The Nenagh River is crossed by Bulfin Road and the N7 (Dublin Road) as well as a railway line to the east. Flood Event Records Nine flood records are listed in floodmaps.ie. The most significant event occurred in an industrial estate off the Dublin Road east of the town centre. 1.2 Relevant information on flooding issues from OPW and LA staff PFRA database comments (in italics): OPW comments Designated APSR on the basis of predictive analysis and historical extents. V. High score - possible wedges, but also historic score of 4 - LA FRS? LA comments No problem in the last 10 years Large scheme in place Swimming pool at risk/flooded? Outside Coolahoggia? Ground water issue, one property at risk, west of Nenagh. [Clare: map shows townland called Coolaholloga, north west of Nenagh, this may be the are Meeting / discussion summary comments: LA comments Clanna / swimming pool area used to flood, including the hotel. However, there has been works carried out and the area is not at significant risk anymore, Potential risk to new housing estate, constructed on an area which is generally marshland, but the properties are generally built on a high ridge. Flood Risk Review Report UoM Nenagh V0_A 1

2 1.4 PFRA Data PFRA hazard mapping PFRA mapping available in GIS layer: No PFRA mapping included on FRR map: No Summary of Principal Receptors Type Nursing_H ESB_HV_Sub UWWTP Arch_Local Arch_Regional Monument_LV Total FRI score (if available) Stage 1 Evaluation Aspect Clearly APSR Uncertain Flood History (1.1) OPW / LA Information (1.2) PFRA Evaluation (1.4) Overall Desktop Evaluation (if any above aspect is uncertain then overall designation is uncertain) 1.8 Proposed level of assessment for Stage 2 site visits Level A Site Visit Level B Site Visit Flood Risk Review Report UoM Nenagh V0_A 2

3 Stage 2: Site Inspection Date and Time of Inspection Names of inspection team (including OPW/LA staff if present) Level A Assessment Date: 03/06/11 Time: 08:00 Mathieu Valois James Murray 2.1 Groundtruthing of Hazard Mapping Fluvial non-tidal Fluvial tidal Coastal Not available PFRA hazard mapping is good in places, however there are some locations where it seems to overestimate flood risk. One particular location is the residential area north of town on the left bank of the Nenagh. From investigating the flood risk on-site it is clear that the properties are not at significant risk. 2.2 Spot check ground-truthing of selected receptor vulnerability (also note any key receptors noted during visit that are not identified by PFRA) Receptor Type Crèche critical infrastructure Nursing home critical infrastructure Sub station Location description (if not obvious) West most tributary East tributary to the Nenagh river Between east tributary and Nenagh River Exists? Overall Vulnerability / Risk (L / M / H) STW On left bank of Nenagh River Industrial Estate Small and Large retail On the Right bank of the Nenagh off the R Local knowledge - on-site comments No on-site comments. (OPW, LA and any info volunteered by local residents during visit) 2.4 Comments on hydraulic constrictions (bridges, etc.) and conveyance routes Most bridges have good capacity. Culvert at crèche has a very low soffit, however channel capacity upstream is significant. Flood Risk Review Report UoM Nenagh V0_A 3

4 2.5 SVRS Assessment Matrix Weightings: A - x1 - reasonable expectation of flooding B - x2 - high expectation of flooding C - x5 - risk to life Property (domestic) Property (small retail or business) Property (large retail or business) Road or Rail Infrastructure Approx. Number 1 to 4 5 to 20 >20 Weighting A B C A B C A B C Critical Infrastructure (local) [hospital, school, police/fire/ambulance station, substation, WTW/WWTW, gov bldg, other (specify)] Critical Infrastructure (national importance) Cultural Heritage Site Environmental Designated Site Hazardous Substances Site Total SVRS Defence Assets Formal and Informal Flood Defence Assets (include effective and ineffective assets to inform asset survey and potential mitigation measures) Open Channel Watercourses Man-made river channel Flood relief channel Canal Mill leat Drainage channels / back drains Bridges and Culvert crossings Single Arch bridge Multi-Arch bridge Single Span bridge Multi-Span bridge Box culvert(s) Pipe culvert(s) Arch Culvert(s) Culverted Watercourses (culvert length is greater than just a crossing) Box culvert(s) Pipe culvert(s) Arch Culvert(s) Irregular Culvert(s) Walls and Embankments Embankment(s) Raised wall(s) Retaining wall(s) Control Structures weirs, gates, dams Fixed crest weir Adjustable weir Dam / Barrage Sluice gates Lock gates Radial gates Storage On-line storage (natural) On-line storage (artificial) Off-line storage Outfalls Flapped outfall(s) into watercourse Unflapped outfall(s) into watercourse i.e. from smaller watercourses, drains etc. into river / estuary / sea Tidal flap(s) Tidal sluice(s) i.e. from main watercourse into estuary / sea Flood Risk Review Report UoM Nenagh V0_A 4

5 Other Pumping Station Erosion Protection Sand Dunes Additional notes (if required): Informal embankment on the right bank of the Nenagh River near the industrial estate that previously flooded has been compromised where a access road has been cut through the embankment. The road seems to be for construction traffic and the embankment may be reinstated after construction is completed. 2.8 Initial Potential Mitigation Measures Non-structural measures Structural measures Planning and Development control Sustainable Urban Drainage Systems Flood forecasting / warning Change in Operating Procedures for water level control: Public awareness campaign Individual property protection Land use management Strategic development management for floodplain development: (integration of measures into strategic development proposals) Storage: On-line Off-line Flow diversion: Flood relief channel Flood relief culvert Increase conveyance: Bridge works Channel works Floodplain Flood defences: Walls Embankments Localised works: Defence raising In-fill gaps Trash screen Maintenance works: Culvert / channel clearance Asset maintenance Relocation of properties: Improve existing defences: (describe) Other (describe): Outcomes PFRA Designation APSR not an APSR IRR FRI Score: Site Ground-truthing of PFRA Assessment (hazard mapping and receptors) Site Visit Review Score 190 Recommended Designation Summary Comments (if required) High Confidence (good) Uncertain Low Confidence (poor) APSR not an APSR IRR Not available While the Nenagh River generally has good in channel capacity and may not flood in lower return periods there is sufficient fluvial flood risk, including a historically proven risk to critical receptors, to warrant Nenaghs designation as an APSR. Flood Risk Review Report UoM Nenagh V0_A 5

6 Photo1: View of Nenagh river, near the swimming pool (on right bank), looking downstream. Photo 2: Gap in left bank embankment near the industrial estate. Photo 3: Confluence of Nenagh River and tributary. Photo 4: Timber piles protecting against erosion, downstream of the confluence. Flood Risk Review Report UoM Nenagh V0_ A 6

7 Nenagh Legend APSR Boundary for CARs only Historic Flooding Incidents Rail Network Roads (National Roads Authority) Airport Land OPW Embankments Historic Flood Data Water bodies mapped from RADARSAT-2 * Hydrometric Gauging Stations EPA River Network Architectural Heritage UNESCO Sites Special Protection Area Special Area for Conservation Rail Stations Nursing Homes Residential Care for the Elderly Proposed National Heritage Area National Heritage Area Benefiting Lands Schools Ports and Harbours OPW Buildings Health Centres Garda Stations Hospitals Fire Stations Flood Extents (PFRA, 2010) 10% AEP Flood Extent (1 in 10 chance in any given year) 1% AEP Flood Extent (1 in 100 chance in any given year) 0.1% AEP Flood Extent (1 in 1000 chance in any given year) Civil Defence Head Quarters * Data Source - Service Régional de Traitement d Image et de Télédétection (SERTIT) (acquired on the 5th of December 2009) Airports Client The PFRA Flood Extents shown are indicative. They have been developed using simple and cost-effective methods that are suitable for the PFRA. They should not be used for local decision-making or any other purpose without verification. Project Shannon CFRAM Study Flood Risk Review Map Title Nenagh Job No. FINAL Scale A3 Drawing Status Figure No. CAR 43 AD/SF Drawn Km Includes Ordnance Survey Ireland data reproduced under OSi Licence number EN Unauthorised reproduction infringes Ordnance Survey Ireland and Government of Ireland copyright, Ordnance Survey Ireland, Copyright reserved Jacobs UK Ltd 95 Bothwell Street, Glasgow, G2 7H Revision Checked JC Review KK/JM Jun 28, 2011 Approved IB/PS